Telephone-transmitter.



J. B. 'EDWARD-s. TELEPHONE TRANSMITTER.l

AIPLIOATION FILED MAY 5, 190'5 Patented- Jan. V12, 1909.

SHEETS-@HEBT 1.

Y 4. www@ 73 B Eidwma'g J. B. EDWARDS. TELEPHONE TRANSMITTER.

APPLIUATION FILED MAY s, 1905.

Patented Jan. l2, 1909.

1s verza: m., wAsmNomN n c UNITED STATES PATENT OFFICE.

JOSEPH B. EDWARDS, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD & SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-TRANSMITTER.

Specification of Letters Patent.

Patented Jan. 12, 1909.

Application led May 5, 1905. Serial No. 258,989.

To all whom t may concern:

Be it known that I, JOSEPH B. EDWARDS, a citizen of the United States of America, and resident of Chicago, county of Cook, and State of Illinois, have invented a new and useful Improvement in Telephone-Transmitters, of which the following is a specification.

My invention relates to telephone transmitters and has for one of its objects the provision of a transmitter in which the usual large, flexible diaphragm is omitted, and in which improved means are used, upon and against which the sound waves are adapted to impinge.

A further object lof my invention is a novel method of securing the chamber for the resistance-varying medium in position, and a novel arrangement of the cooperating' parts of said chamber.

The other improved features of my invention will more clearly appear from the following dscription of the drawings, which illustrate modifications of my transmitter which I have worked out for the purpose of disclosing the underlying principles of my invention, and in which:

Figure 1 represents a sectional view of a transmitter embodying one form of my invention; Fig. 2 is a rear view of the chamber or recess for the resistance-varying material showing parts of the transmitter broken away and with portions thereof removed; Fig. 8 is a rear view of the transmitter with the rear-inclosing casing removed and drawn to a smaller scale; Fig. 4 is a view of the working parts of the transmitter disassem bled and drawn to a reduced scale; Fig. 5 is a sectional view of another form of my invention; Fig. 6 is a rear view of the chamber' for the comminuted conducting material showing the spring 26 in engagement therewith; Fig. 8 is a rear view of the form shown in Fig. 5 with the inclosing casing removed and drawn to a reduced scale; Fig. 7 is a view of the working parts of the transmitter disassembled.

In the preferred form of my invention I provide a front plate 1 within a central aperture in which a suitable mouth-piece 2 isadapted to be secured in the usual manner; a bridge plate 3 is adapted to rest upon Y the inner face ofthe main plate 1 and is preferably insulated therefrom by an insulating ring 4 or in any suitable manner and is held in position by the pressure of springs 25. The plate 3 is shown as consisting of an annular cup-shaped member, the forwardlyextending rim or flange of said memberbeing adapted to rest upon the insulating material 4, said flange forming a suitable housing for the main diaphragm 5. A Any other form of the plate 3 may be adopted in lieu of that shown. A second bridge piece or supporting plate 6 is adapted to rest preferably upon the shoulders 7, 7, formed upon the inner surface of the main plate 1, and is secured thereto in the present instance by the screws S, 8, insulating material 9 being preferably disposed between the plate 1 and the ends of the supporting plate or bridge 6.

A recess or chamber 10 -is preferably formed of thin sheet metal and is adapted to be closed upon one side by a small flexible diaphragm 11 of mica, parchment or other suitable material. In practice I prefer to secure the periphery of the flexible diaphragm 11 between the flange 12 formed upon the chamber or recess l0, and a ring 18, the periphery of said diaphragm being secured between said ange and ring by small screws 14, 14. An electrode 15, preferably of carbon, is secured within the `chamber 10, said electrode in the present instance being electroplated and soldered to a metallic' plate or support 16. The plater16 has a centrally disposed pin 17 formed thereon, adapted to project through the forward wall of the chamber 10 and adapted to receive a nut 18 adapted to clamp the electrode 15 within the chamber' 10, said pin being also adapted to securely clamp the diaphragm rigidly upon the chamber or recess 10. A similar electrode 19, similarly carried upon a plate 20, is disposed upon the inner face of the iexible diaphragm 11 and is adapted to be clamped in position thereon by means of a suitable block 21, and an extended end of the pin 22 extending vthrough said block and adapted to receive the nut 28. Any suitable comminuted conducting material 24, such as carbon granules, may be disposed between the electrodes 15 and 19, and is adapted to vary the resistance of the current passing therethrough to create voice currents in the well-known manner. scribed the construction ofthe chamberflO VVvhile` I haveV de-v and the arrangements of the-parts secured thereto in detail, it will be understood that the constructiondescribed may be varied as to such details, and that my invention is not limited to the construction'and arrangement or' such parts as shown and described out contemplates any suitable construction thereof.

A Suitable, Sprng25 is carried by the Supportingfplate 3, said spring being shown as a ring having an inner rearwardly deflected edge, said edge being adapted to engage the chamber l0, and to coperate with a Spring 26, secu-red vto the .bridge'or supporting yplate @the free end of said last-mentioned spring bei-ng :also adapted to .engage the chamber l0, said `chamber being secured in position between seid springs 25 and 26. A ring of felt, 27, maybe disposed between the chambei* 10 and spring 25, but this is not essential. Carried upon the plate-or bridge-piece 6 is a block 98 Secured thereto by screws 29, said screws being yinsulated from said block and engaging 'the bridge 6, said block being also insulate from said bridge plate as shown. A binding screw 30 is carried by the block (see Fig. l3) and constitutes one side of the Acirouit'of ythe transmitter. .Also prefer.- ably mounted upon the plate 6 is a block 31 carrying `an :insulating 4bushing 33 and a binding screw y32 adapted to engage a conduetor', said bindingscrew constituting a terminal for the other side of .the transmitter circuit. The circuit of the transmitter ex-` tends from the binding post 30 through the block 2 8 and the pin 22 to the rear electrode 19, through the comminuted conducting ma- 24 to the front electrode 15 and thence threugh the*chamber 10. to the binding screw 32 .by means of a conductor 34 secured to seid chamber in any suitable manner. A set 35 (Fig. 3) isv threaded into the block 2,'8 and is adapted to engage the post 2.1., said Set Y screw being adapted to secure the rear eleotrode 1,9 in an adjusted position Within the block 28- The realeleotrode 19 and the chamber 10 is irst adjusted. in position between the opposite free ends. of the Springs 25 and 2.6 and is then secured. in suoh adjust ed position by means ofthe set screw 35,. A metallic inolosing casing 36 is provided for the rear portion of the transmitter, said. eas-V ing being adapted t0 inclose the interior thereof, the rear face of Said casing adapted to secure the. transmitter to a Suitaie transmitter arm or other support, and having apertures therein for the leadingin. wires The casing 36 may he secured to the transmitter in any Suitable manner RS hy the screws 37, 3T

It will he noted that the diaphragm 5 is preerably a rigid non-fiexhle diaphragm, eonsisting of a circular disk of sheety metal and Shown mounted, direotly P011 theehamber 1Q, but said dia hragm may be associated with said cham er or one of the elec-` trodes thereof in any suitable manner. The diaphragm in the present instance is free labout its periphery, from the other parts of the transmitter', and is adapted to present an enlarged surface to the lncoming sound waves against which the sound Waves may impinge. The rigid diaphragm obviates the. necessity for the use of the usual large exible diaphragm, the periphery of which is ordinarily adapted to engage a part of the transmitter frame, said perlphery carrying resilient material between Which resilient material and dampening springs, adapted to engage the body of the diaphragm, the diaphragm is usually adjusted, in order to impart thereto the proper degree of ilexibility. No adjustment of any kind of the large 'diaphragm ,adapted to receive the sound waves is necessary in my improved transmitter, the proper variations of resistance in the comminuted conducting material being obtained entirely by adjusting the small flexible diaphragm 11 between the springs 25 and 26, as kabove described, said adjustment being maintained by means of the set screw 35.

In Figs.. 5 to 8, inclusive, I have illustrated another form of my invention in which the bridge plate v3 consists of a bar or a strip resting Aupon shoulders 88 carried upon the interior surface of the plate 1, the bridge plate 6 being adapted to rest upon the ends of said bridge 3, and Vbeing secured thereto, and to the plate l by means of screws 39, 39, said screws being insulated therefrom, and fom vthe plate 3 by suitable insulating material, as Shown. The binding post 32 is carried by one 0f the, Screws `29 adapted to secure the block, 28 in position, said binding screw being carried upon a metallic strip 40, said stri bein secured in position by andinsulated irom te Screw 29, as shown in Fig. 5. A disk of oiledpaper 41 is preferably secured in osition between the chamber 1() and the diaphragm 5, the edge of said disk being'dispos'ed between the plate 1 and the bridge piece 3", said being .adapted vto exclude dust and particles of dirt from the interior of the transmitter.

VVhijle I have illustrated but two modificatOnS of my invention it will be understood that many commercial forms'thereof may be devised and that I do not wish to limit the principle of my invention to the modifications herein shown and described.

What I claim was new and desire to secure by Letters Batent is.:

1. In a telephone transmitter, the combination with a granule containin chamber, of a diaphragm supported thee y and vibratory therewith as a whole, a iiexible diaphragm forming the rear wall of chamber, other resilient means su porting said chamber, a stationary electro e and amovable electrodey Within the chamber, the vibration of the chamber being adapted to agitate the granules therein to prevent packing, substantially as described.

f 2. In a telephone transmitter, the combidescribed.

3. In a telephone transmitter, the combination with a suitable chamber adapted to contain comminuted conducting material, of a flexible diaphragm adapted to inclose `the open end of said chamber, a suitable electrode associated with said diaphragm, a nonfiexible diaphragm associated with the opposite end of said chamber, a pair of springs, said chamber and said diaphragm being adapted to be adjusted in position between the oppositely deflected ends of said springs, and means for securing said parts in adf justed position, substantially as described.

4L. In a telephone transmitter, the combination with a chamber, of a diaphragm adapted to form a flexible wall for said chamber, comminuted conducting material within said chamber, a pair of oppositely deflected springs said chamber and said diaphragm being resiliently mounted between the deflected ends of said springs, substantially as described.

5. In a telephone transmitter, the combination with a suitable chamber or recess adapted to contain comminuted conducting material, of a flexible diaphragm adapted to inclose the open end of said chamber, a suitable electrode associated with said diapbragm, a non-flexible diaphragm, against which the sound waves are adapted to impinge, associated with said chamber, a pair of oppositely deflected springs said chamber and said diaphragm being resiliently mounted between the ends of the said springs, substantially as described.

Signed by me at Chicago, county of Cook, and State of Illinois, in the presence of two witnesses.

JOSEPH B. EDWARDS.

Witnesses:

C. P. BELDEN, E. M. KING. 

